1. Field of Invention
The present invention relates to sectorized wireless communication systems, and more particularly, to methods and systems for providing adjustable sector configurations across wireless cells.
2. Description of the Prior Art
As wireless communications become more widely used, the demand for limited wireless resources, such as the finite number of frequency bands, time divisions, and/or identifying codes (collectively referred to herein as xe2x80x9cchannelsxe2x80x9d) have increased significantly. It should be appreciated that channels may be distinguishable based on the particular air interface standard implemented such as the frequency bands of frequency division multiple access (FDMA), time slots of time division multiple access (TDMA and W-TDMA), pseudo random codes of code division multiple access (CDMA and W-CDMA), and the like. In order to more efficiently use these available resources, wireless communication systems typically divide a geographic area into multiple overlapping coverage cells, which are each served by a base station. Each base station typically comprises a tower, one or more antennas, and radio equipment to allow wireless communication devices to connect with the network side of a wireless communications link.
Conventional wireless communication systems utilize a variety of schemes for providing comprehensive coverage of an area while providing sufficient communication capacity without an undesirable level of interference. For example, one scheme includes using particular antenna radiation patterns such as sectorization. Using narrow-beam antennas, a coverage cell may be divided into smaller areas, called sectors, each having a specific radial coverage area within the cell. The antenna(s) defining a particular sector provide wireless communication capacity to wireless devices within the sectors"" specific radial coverage area. In addition, sectors are typically configured to overlap with adjacent sectors to provide seamless communications to wireless devices moving between sectors.
In a conventional wireless communication system, a cell is typically broken into three to six equal sectors. However, the coverage area or shape of the sectors typically depends upon the geographic area the sector comprises. In other words, even with the same antenna array and transmitting power configuration, the shape of each sector typically differs based on such factors as climatic changes, differences in terrain, development, etc. For example, a sector in which there are a large number of tall buildings will typically have a different coverage area shape than a sector in which there is mostly dense foliage.
Further, the shape of a sector can vary dynamically with environmental changes leading to areas where coverage is absent. These areas, called xe2x80x9cdead spots,xe2x80x9d are often caused by physical barriers such as hills, tunnels, and the like. In addition, the varying shape of a sector can reduce or eliminate the overlap between adjacent sectors and adjacent cells leading to dropped communications. Thus, it would be advantageous to more efficiently use wireless capacity by dynamically adjusting the shape of sectors in order to avoid dead spots and dropped communications.
In addition, adding or moving base stations in a conventional wireless communication system requires considerable planning to determine the precise locations of each base station to ensure that the entire coverage area of the system is covered without dead spots or redundancy. Such planning typically includes the physical mapping of the coverage area. For example, one conventional method of mapping a coverage cell comprises placing a transceiver on a mobile unit such as an automobile and measuring the reception as the unit moves throughout the area. Because cell mapping can be costly and time consuming, it would be advantageous for base stations to dynamically map cells based on communications received from wireless devices.
Accordingly, methods and systems are provided to address the above and other problems of the prior art.
Methods and systems consistent with the invention, as embodied and broadly described herein, comprise a method for adjusting coverage in a wireless communication system. In one embodiment of the present invention, measurements performed by at least one wireless device at a first cell having a first coverage area is received at the first cell. Upon receiving the measurement information, the first coverage area is determined based on the received measurement information. The first cell then transmits information about the first coverage area to a second cell having a second coverage area. Upon receipt, the second cell may then use the received first coverage area information to adjust the second coverage area.
In another embodiment, such methods and systems comprise a method for mapping coverage in a wireless communication system. In accordance with the invention, a plurality of wireless devices is provided at a first cell having a first coverage area. The power of the first cell is monitored by the plurality of wireless devices and collected by the first cell. Based on the collected power information, the first coverage area is mapped.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed. Additional objects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention will be realized and attained by means of the elements and combinations particularly pointed out in the appended claims. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate several embodiments of the invention and together with the description serve to explain the principles of the invention.